The present invention includes embodiments directed to the field of wireless local area networks (WLANs) comprised of a number of wireless access points (APs). In a typical WLAN, it is common to use APs having more than one radio occupying different service frequency bands and/or different channels within a band. In a WLAN, an AP can have an overlapping coverage area with one or more other APs. When coverage areas overlap, any single client entering the network has a discrete set of (different) probabilities of entering via more than one AP radio. If there is a large incidence of overlapped coverage within a WLAN system, the load of wireless traffic can become skewed so that a large portion of the load is handled by only a portion of AP radios, while other AP radios are neglected. This leaves the network in a sub-optimal operational state.
This scenario is very likely in multichannel APs, where so-called “sectorized antennas” are in fact overlapping in a large portion of their coverage areas. When the load is imbalanced in this fashion, packet collisions increase and thus throughput is compromised, since the WLAN has unused capacity. Since network utilization is improperly distributed, other problems typically associated with an overcrowded network are observed, such as reduced quality of service and so forth.
It is therefore desirable to obtain a load balance of client wireless traffic between AP radios in order to maximize throughput and minimize latency for the wireless subsystem. Load-balancing algorithms have previously been devised to kick some clients off a particular AP radio to allow it to associate with another radio and thereby achieve a more balanced distribution of wireless traffic. Directed re-association has also been used, in which a particular client is specifically instructed to contact a particular AP for re-association. Traditional load balancing algorithms typically use heuristics and parameters tailored to specific operational scenarios. Hence, significant network testing for a particular scenario is required to establish the operational guidelines required by such approaches. Classic approaches include the threshold algorithm, central algorithm, Centrex algorithm, and hybrids thereof, as are understood in the art. All of these approaches suffer in performance when the system characteristics fluctuate significantly (as they do in a practical WLAN system). Thus, no previous-type approaches have been able to provide a satisfactory solution to the problems of obtaining a load balance.